_memavl.gml

开放源码的编译器open watcom 1.6.0版的源代码

.func _memavl
#include <malloc.h>
size_t _memavl( void );
.ixfunc2 '&Memory' &func
.funcend
.desc begin
The &func function returns the number of bytes of memory available for
dynamic memory allocation in the near heap (the default data segment).
In the tiny, small and medium memory models, the default data segment
is only extended as needed to satisfy requests for memory allocation.
Therefore, you will need to call
.kw _nheapgrow
in these memory models before calling &func in order to get a
meaningful result.
.pp
The number returned by &func may not represent a single contiguous
block of memory.
Use the
.kw _memmax
function to find the largest contiguous block of memory that can be
allocated.
.desc end
.return begin
The &func function returns the number of bytes of memory available
for dynamic memory allocation in the near heap (the default data segment).
.return end
.see begin
.seelist _memavl calloc Functions _freect _memmax
.seelist _memavl _heapgrow Functions malloc Functions realloc Functions
.see end
.exmp begin
#include <stdio.h>
#include <malloc.h>

void main()
  {
    char *p;
    char *fmt = "Memory available = %u\n";
.exmp break
    printf( fmt, _memavl() );
    _nheapgrow();
    printf( fmt, _memavl() );
    p = (char *) malloc( 2000 );
    printf( fmt, _memavl() );
  }
.exmp output
Memory available = 0
Memory available = 62732
Memory available = 60730
.exmp end
.class WATCOM
.system